Laminated magnet core

ABSTRACT

A laminated magnet core for contactors and the like has a working airgap. The magnet core is made up of a stack of metal sheets that define a path of flow of magnetic flux through the core. The metal sheets have respective elongated slitlike openings extending across a portion of the width of the sheets. The openings at least partly overlapped and jointly define a gap for reducing core remanence. The elongated slitlike openings have respective longitudinal axes that intersect the path of flow of the magnetic flux in the core at an acute angle.

United States Patent US. Cl

Gunther Bohlke Amberg, Germany Sept. 2, 1970 Dec. 7, 1971 Siemens Aktlengesellschalt Berlin, Germany Jan. 28, 1970 Germany Inventor Appl. No. Filed Patented Assignee Priority LAMINATED MAGNET CORE 4 Claims, 2 Drawing Figs.

335/281, 335/297, 336/234 lnt.Cl H0lf3/00 FieldofSearch 335/227. 281, 297; 336/234 [56] References Cited UNITED STATES PATENTS 2,313,527 3/1943 Edwards 335/227 X 2,952,801 9/1960 Hyink 335/281 X 3,188,427 6/1965 Cooper et a1. 335/281 X FOREIGN PATENTS 241,584 12/1964 Austria 335/281 Primary Examiner-G. Harris Attorneys-Curt M. Avery, Arthur E. Wilfond, Herbert L.

Lerner and Daniel J. Tick ABSTRACT: A laminated magnet core for contactors and the like has a working airgap. The magnet core is made up of a stack of metal sheets that define a path of flow of magnetic flux through the core. The metal sheets have respective elongated slitlike openings extending across a portion of the width of the sheets. The openings at least partly overlapped and jointly define a gap for reducing core remanence. The elongated slitlike openings have respective longitudinal axes that intersect the path of flow of the magnetic flux in the core at an acute angle.

LAMINATED MAGNET CORE My invention relates to laminated magnet cores made up of stacked metal sheets, especially U-shaped magnet cores for contactors and the like. More particularly, my invention relates to laminated magnet cores wherein openings in respective sheets define a gap extending transversely through the core body, the gap serving to reduce core remanence.

The invention is related to those disclosed in copending applications of G. Rauter, Ser. No. 69,002, filed Sept. 9, I970 claiming a German priority of May 2, 1970; and O. Muller and G. Rauter, Ser. No. 69,003, filed Sept. 2, I970 claiming a German priority of Sept. 4, 1969, these applications being assigned to the assignee of the present invention.

Copending application, Ser. No. 69,003 discloses a U- shaped magnet core made up of laminated metal sheets having respective openings therein which jointly define a slot extending transversely through the core.

It is an object of my invention to provide a laminated magnet core having means for effecting a reduction of core remanence.

It is another object of my invention to provide a laminated magnet core having a gap for reducing core remanence that is easily produced. Subsidiary to this object, it is an object of my invention to provide a magnet core of the kind referred to above wherein the production of the core is simplified with regard to holding tolerances.

It is another object of my invention to provide a laminated magnetic core having'core remanence reduction means that has characteristics which do change with operation of the magnet core.

It is still another object of my invention to provide a magnet core having a gap for reducing core remanence while at the same time affording a high structural stability.

Because of the kind of magnet core referred to above in connection with the copending applications, it has become possible to provide a U-shaped magnet core for contactors wherein an airgap for reducing core remanence is producible in a simple manner. In addition, such cores can be constructed so that their characteristics do not change with operation of the magnet core. The instant invention improves the laminated core in that the production of the airgap is simplified especially in view of the tolerances which have to be maintained. This is achieved, according to a feature of the invention, by providing metal sheets of the magnet core with respective elongated slitlike openings that extend across a portion of the width of the sheets, these slitlike openings having respective longitudinal axes intersecting the path of the flow of magnetic flux at an acute angle. The openings at least partly overlap and jointly define a gap extending transversely through the core body for reducing core remanence.

According to another feature of the invention, the stability of the magnet core is increased without filling the aforementioned gap while at the same time providing the necessary magnetic resistance for reducing core remanence by arranging the slitlike openings of the respective sheets such that the openings of each two adjacent sheets of the stack partially overlap each other.

According to a further feature of the invention, an increase in the airgap area is obtained by configuring the slitlike openings in the respective metal sheets so that they have a zigzag shape. In an especially advantageous form of the sliklike opening, which takes into account a good stability of the magnet core and the desired magnetic resistance, is achieved by having two groups of openings, one group being M-shaped and the other group being V-shaped Every second sheet of the stack is provided with an M-shaped opening and the remaining sheets are provided with V-shaped openings. The V-shaped opening is disposed so that the bight portion thereof overlaps a portion of the M-shaped opening.

The invention will now be described with reference to the and FIG. 2 illustrates a magnet core wherein the metal sheets thereof are provided with difi'erent openings that partially overlap each other as required by another embodiment of the invention.

Referring to FIG. 1, magnet core 1 is made up of magnetic sheets 2, the openings 3 are Z-shaped and the bridging or carrier portions of the plates 2 are designated by reference numeral 4. In FIG. 2, the consecutive sheets are alternately provided with M-shaped and V-shaped openings. The remaining airgap defined by the partially overlapping M and Vshaped openings is designated by reference numeral 5. This airgap together with the remaining portions of the slitlike openings 6 and 7 form the airgap for reducing core remanence.

It is evident especially in the embodiment according to FIG. 2 that the stability of the magnet core 1 is improved for example over configurations of the kind illustrated in FIG. I: first, the remaining carrier portion 4 is held large, and second, parts 6 and 7 of the slitlike openings effect no weakening of the mechanical stability of the magnet core because of the full cross section of every second sheet with respect to the remaining sheets.

The arrangement according to the invention affords the additional advantage that because of the lengthening of the airgap, the airgap width for achieving the same remanence power is increased so that the openings can be formed with stamping tools provided with a stamping portion having a larger width. Because of the advantageous arrangement of the slitlike openings, it is possible to eliminate any filling of the openings with a mixture of synthetic material and iron powder or with a synthetic material.

Upon a study of this disclosure it will be apparent to those skilled in the art that my invention permits of various modifications and consequently may be given embodiments other than particularly described and illustrated herein, without departing from the essential features of my invention and within the scope of the claims annexed hereto.

I claim:

1. A laminated magnet core for contactors and the like having a working airgap, the magnet core comprising a stack of metal sheets defining a path of flow of magnetic flux therethrough, said metal sheets having respective elongated slitlike openings extending across a portion of the width of said sheets, said openings being at least partly overlapping and jointly defining a gap extending transversely through said core for reducing core remanence, said elongated slitlike openings having respective longitudinal axes intersecting the path of flow of said magnetic flux in said core at an acute angle.

2. A magnet core according to claim 1, saidelongated slitlike openings having a zigzag configuration.

3. A magnet core according to claim 1, said openings being locatedin said sheets of said stack so that each two adjacent openings partially overlap each other.

4. A magnet core according to claim 3, each openings consisting of two groups, the openings of one of said groups being M-shaped, the openings of the other one of said groups being V-shaped each second sheet of said stack having one of said M-shaped openings, and each of the remaining sheets of said stack having one of said V-shaped openings, said V-shaped openings being disposed in said remaining sheets so that the bight portion thereof overlaps a portion of said M-shaped openings.

1' v as 

1. A laminated magnet core for contactors and the like having a working airgap, the magnet core comprising a stack of metal sheets defining a path of flow of magnetic flux therethrough, said metal sheets having respective elongated slitlike openings extending across a portion of the width of said sheets, said openings being at least partly overlapping and jointly defining a gap extending transversely through said core for reducing core remanence, said elongated slitlike openings having respective longitudinal axes intersecting the path of flow of said magnetic flux in said core at an acute angle.
 2. A magnEt core according to claim 1, said elongated slitlike openings having a zigzag configuration.
 3. A magnet core according to claim 1, said openings being located in said sheets of said stack so that each two adjacent openings partially overlap each other.
 4. A magnet core according to claim 3, each openings consisting of two groups, the openings of one of said groups being M-shaped, the openings of the other one of said groups being V-shaped each second sheet of said stack having one of said M-shaped openings, and each of the remaining sheets of said stack having one of said V-shaped openings, said V-shaped openings being disposed in said remaining sheets so that the bight portion thereof overlaps a portion of said M-shaped openings. 